


Fishtanks and Tailfins

by TheSocialExperiment



Category: Attack on Titan, Shingeki no Kyojin, aot, snk - Fandom
Genre: Human AU, M/M, Modern AU, mermaid au
Language: English
Status: Completed
Published: 2014-04-11
Updated: 2014-08-19
Packaged: 2018-01-19 01:52:14
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 8
Words: 4,949
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1451002
Author URL: https://archiveofourown.org/users/TheSocialExperiment/pseuds/TheSocialExperiment
Summary: <blockquote class="userstuff">
              <p>An Attack on Titan modern AU where Eren is a mermaid and Erwin is a diver. I have no idea where I'm going with this, I just saw the idea on tumblr and wanted to write it.</p>
            </blockquote>





	1. Chapter 1

It was early morning when Erwin arrived at the beach, his gear already mostly on due to how difficult it was to put on in sand. His wetsuit was half on, arms hanging at his waist, exposing his muscular body. The black wetsuit hugged his hips and shoulders as he stretched from stiffness of the car ride.

He was a scuba diver. He'd taken up the hobby after falling in love with the ocean and it's varying life forms. The man was searching for a cove he had found as a child currently. He wasn't permitted to enter the water then. His mother worried about sharks in the warm waters and currents that would steal away her little boy, but now he could protect himself from both. 

His blonde hair fell in his face as he trekked over the white sand to the cove. His gear creaked with every step. The water was in the cove was clear and blue as it reflected the morning rays. He scanned the surface, hoping to spot the fish he'd seen last time. 

A large fin, a flash of green-ish scales; that's all he remembered seeing. It was gone before he could blink. Then his mother was calling and he couldn't investigate what he thought he saw. He later convinced himself the he was delusional and the it was only a huge fish, or like his mother feared, a shark. 

Years later, Erwin sat at the waters edge of that same cove and secured his mask and fin straps. He took one experimental breath before inching fully into the warm water. Sunlight streamed through cracks and holes in the rock, lighting up the cove with brilliant blue on white sand. 

Artificial tasting oxygen flowed through his mask. His heart sped up as he gracefully kicked through the water. It was much deeper than he anticipated. He could barely see the bottom, even with the clarity of the water. 

Coral grew scraggly along the walls. Tiny fish darted in front of him, teasing the slower human with their speed. A flash of seemingly familiar blue scales caught his eye from behind a rock formation. He swam closer, trying to see behind it. 

Just then, Erwin's diving knife fell out of his belt and began floating downwards. Scrambling to grab it, Erwin ripped out the tube to his oxygen tank. He quickly drew in what he knew would be his final breath from his tank before his mask filled with water. 

Trying not to panic, he lowered his mask around his neck and opened his eyes. The salt water stung, but he could see. The surface was too far up. Nonetheless, he swam up, powerful strokes of his legs propelling him towards the surface. 

Too soon, his lungs began to burn and his vision wavered. Another blue flash from below startled him. He twirled around, trying to get one glimpse of the aquatic creature before blacking out. Nothing. Just the small, serene fish and the perpetually undisturbed sand. 

A gentle hand on his face guided his face upwards. Brown hair floated around a pale face, framing it with a halo of golden strands. Bright green eyes met Erwin's blue. Circular patterns were etched on his face and torso, twisting and twirling until they reached his tail fin. His tail fin. He had a tail fin. 

His face twisted with confusion as he stared down at the human turning a blue-ish tint below him. Realization dawned on him when he saw the mask around Erwin's neck. 

The mermaid pulled Erwin up into a kiss, blowing a few bursts of air into his lungs. The burning stopped as Erwin breathed, taking forced air from the brown haired mermaid. His hand was still on the man's face. 

The green eyed mermaid drew back, face reddened with effort. His gills flashed open for an instant, then tiny holes alongside the slits opened, releasing the water back into the ocean. He grabbed the blonde human's wrist and began dragging him upwards. 

Erwin was too startled to move at first, then started kicking, trying not to be deadweight on the mermaid. His tail, which was actually a mixture of blue and green, whipped back and forth. It hit Erwin's legs a few times, no doubtably creating bruises.

When they broke the surface, both gasped in unison. Their eyes locked on each other's in a moment of seriousness before dissolving into laughter. Erwin's laugh was deep and echoed in the cove. The mermaid's was higher pitched, lilting and genuinely amused. 

"Thank you," Erwin managed to say through his laughter, trying to wipe away tears that were forming at the corner of his eyes. 

The boy stared at him for a few seconds, a blush spreading across his cheeks. He forgot the social custom of humans to respond as he fought his urge to flee from this forbidden human that was so beautiful. Jagged and rough, so unlike the streamlined mermaid, but graceful. The mermaid had watched him from the moment he got in the water. 

"Can you understand me?" Erwin asked. His face was puzzled as he inspected the conflicted mermaid. The boy forced a laugh and smiled at the diver. 

"Of course. And no problem. You seemed like you were having some trouble," he responded, waving his hands, trying to play his nervousness off as a joking personality. 

"No, seriously, thank you. I wouldn't have made it to the surface in time." Erwin's face grew solemn. 

"You show grow a pair of these," the boy said, tapping his partly open gills. 

"I should. No more masks that break at the worst possible time," Erwin grumbled, tugging at the mask around his neck. He had floated back and was now standing on the sandbank. The shallow water lapped at his stomach as if it didn't almost just drown him. "What's your name, by the way?"

"Jaeger. Eren Jaeger. And yours?"

"Erwin Smith, at your service, Eren."


	2. Chapter 2

The two had talked for hours as the sun traveled across the sky. Erwin had gone to his car and changed. He put his gear away and got out a towel to lay on and some food. Eren stretched out on the shore, his tailfin emerged in water while his torso rested on the white sand. 

They shared the sandwiches and drinks as they talked about themselves and their families. 

Eren spoke of his sister Mikasa and his best friend Armin. Erwin spoke of his childhood friend Levi, and their four friends; Petra, Gunter, Auruo, and Erd. 

As morning turned into day, Eren became more and more anxious, looking out at the beach frequently. 

"I can tell you need to go...but...can we meet again?" Erwin inquired, not wanting to lose the green eyed mermaid. 

"I don't exist according to your people. We never met. But you really do like diving here, since you come every morning. But that has nothing to do with anything," Eren said, faking boredom with a glint in his eyes. 

Erwin grinned, catching on fast after a brief disappointment. Eren didn't miss the flash of sadness that crossed the diver's face. 

'He has a nice smile,' Eren thought as he looked up at the forbidden human. 'I just can't let Mikasa or Armin find out. Mainly just Mikasa.'

A car pulled into the parking lot. Eren jerked back, fully submerging his tailfin again. Erwin picked his basket up. 

"See you tomorrow?" 

Eren nodded and smiled before sinking down into the depths of the cove. His tailfin flashed above the surface for an instant before disappearing. He was gone. 

It was only 10:30 AM. Erwin had time to go research before he had to work. He drove home, hands shaking from the experience. 

'I met a mermaid. A mermaid. A merman? I met a merman. A mermaid. I have no idea.'

He pulled into his house. It was a small white house, a two bedroom. He ran into his office, grabbing the laptop off his desk. 

He typed in the word 'mermaid'. All the links were conspiracy related or about how to make a mermaid costume. 

He searched 'mermaid male Pacific Ocean', no results, just fanart of things he didn't understand. 

Frustrated, he began searching the conspiracy sites for anything that resembled Eren. All the sites showed female mermaids with sharp teeth and dagger nails. 

No sites showed or talked about the swirling tattoos, nor about male mermaids. 

Erwin sighed and closed his laptop. It was nearly time to go to work. He got ready, taking a shower and putting on a suit. Thinking about mermaids and fantasy creatures would have to wait till tomorrow.

**Notes for the Chapter:**

> Yay! Two chapters! Leave a comment if you see any mistakes, I'll fix them right away.


	3. Chapter 3

FTaTF 3

Morning came too early. Erwin had stayed at the office late, getting piles of paperwork sorted. 

He groaned and rolled over, wanting to go back to sleep instead of going diving. 

Eren's eyes flashed in his mind, and he shot up in his bed. He groaned again when he realized he hadn't fixed his mask from yesterday. He jumped in the car with coffee for him and lunch for two and began driving. 

He sat in the car, wetsuit on, fiddling with his mask at the beach. Finally fixing it, he put it on and took an experimental breath. It worked. The tank was still full from yesterday since his dive was cut short. 

He walked to the cove, more energetic than he'd felt in years. The beach was abandoned. The rising sun lit the cove up red and yellow. 

The man sat on the waterline, the water lapping at his feet as he drank his coffee. The cove water was calm, small waves barely disturbing the surface, but the waves crashed violently outside. 

A splash captured his attention. He looked up to see Eren grinning at him from the water. 

"So you came," he said, smile never faltering. 

"Of course. Want breakfast? I brought some muffins." 

Eren shook his head. "Your food kinda makes me sick. No offense. I'm sure you wouldn't want to eat raw fish and seaweed."

"Fair enough," Erwin laughed. 

Soon after, Erwin joined Eren in the water. They dove together, the mermaid spiraling around the slow human. 

Eren blew bubbles up at Erwin, creating small whirling spots with a wave of his hand. 

Erwin grabbed Eren's webbed hands in his and spun them around, tumbling over each other. They both laughed, bubbles rising out of Erwin's mask. 

The tattoos on Eren's body moved, spinning and twisting into new patterns, then returning to the old patterns before changing again. 

They were forced to go back to the surface, Erwin finally out of air. They broke the surface, gasping and red. Eren's tattoos were still spinning. 

"Why do they do that?" Erwin asked when he finally caught his breath. He ran his hand across the mermaid's cheek. He could feel the markings squirm beneath his touch. 

"Do what?" Eren asked. He looked down at his body, then gasped. 

"I don't know! They've never moved before!" He exclaimed, face twisting up. He pulled away from Erwin. 

"I need...to go home...Armin will know what happened. I'm sorry. We'll meet again, here, three days time. If I can't make it...well, I don't know."

Erwin pulled the mermaid into an awkward hug, considering there was his equipment plus Eren's tail. Eren touched both sides of the blonde's face. 

He murmured a few quick words. His hands glowed green. A warm feeling spread through Erwin's body. 

"That was a good luck charm, of sorts. Be safe," the mermaid chirped. And then he was gone to the depths of the ocean. 

Erwin left the water, blood running cold at the thought of never seeing Eren again. This was going to be long three days.


	4. Chapter 4

Three days had passed. Erwin had gone to the cove every day to dive. He practiced tight turns and flips. He explored a small underground tunnel system. Many colorful fish prodded at him curiously. He had a small purple fish follow him for most of one day, darting in front of his face. 

On the third day, Erwin chose to forgo all of his equipment except for his swimsuit and goggles. He floated on his back and waited. 

He was startled from his relaxed state by a stream of bubbles being released below him. They tickled his skin. 

Erwin panicked as two arms wrapped around his waist and started tugging him down. 

"Shhhh, just trust me. Now close your eyes," Eren murmured as he pulled Erwin down into the water barely past his shoulders. He stopped when Erwin protested, eyes shut tightly. 

"Eren, you know I can't breath underwater."

"And you know I can't go on land so you're going to have to fucking trust me Erwin."

Shivers ran up the man's spine when the mermaid hissed his name. His eyes were squeezed shut, much to his displeasure. He wanted to see his green eyed companion, run his hands over his body and make sure he wasn't harmed. 

"Can I open my eyes?"

"No. Okay, on a count of three, we're going under, then open your eyes," Eren commanded. Erwin nodded obediently. 

"One. Two. Three!" 

Erwin took a breath and let Eren pull him down. He opened his eyes as his head went under. No burning salt water flooded his eyes like it always did. 

A bubble of air surrounded his torso, stopping just above his hips and stretching to a few inches above his hair. He reached out and touched the edge. His fingers went through. He could feel the water, but when he drew his hand back in, only a few drops of water clung to his fingertips. 

Eren grinned at him from a foot away, pride and cockiness showing clearly on the youth's face. 

"We learned it a few days ago. I've been practicing so I could take you to my world. Now, you can swim around and breath, since it extracts air from the water."

"I thought you were in trouble! I came here everyday looking for you," Erwin scolded. 

"Well, my teacher Hanji said it happens when mermaids...imprint. She said they don't teach us about it until we're older because it rarely happens before 25-ish."

Erwin took a breath in. "What is 'imprinting?'" 

Eren looked at his hands, the webs translucent in the water. 

"It's...when...uh...a mermaid finds his or her life partner. Usually both mermaid's tattoos swirl until they reach a rhythm, then they stay in sync until one of the partners dies."

"But...um, Eren...what?"

"I know. I asked my professor Hanji. She was more interested in our relationship than angry about me breaching the surface. She wants to study us. She said this hasn't happened in decades."

"I don't have the tattoos though. So yours won't be able to sync, right?"

"That's what Professor wants to study. I mean, she suggested you undergoing the ritual and getting yours, but I figured it's not normal for humans."

Erwin hesitated, pawing at the edge of the bubble. It was getting colder as they drifted down. Eren's tattoos spun in dizzying patterns. It made his skin crawl. 

"I...don't know what to say right now. Life partner? It's overwhelming."

Eren's face contorted with sadness. He knew this would happen. 

Erwin brushed the hair out of Eren's face. "Don't make that face. We'll just see where this goes, okay? I'm older than you. We can't rush into this."

Eren hesitated. "How...old are you?" 

"36."

"I'm 22," Eren said. Erwin just nodded. 

"I should be going to work now, I suppose," he said as he started working his way back up to the surface. Eren swam circles around the bubble, nervously swishing his tail. 

When Erwin got close to the surface, the bubble collapsed in on itself. The blonde man spluttered as he lost his support. 

When get broke the surface, Eren had already left, pouting like the child he was. 

"This isn't good for my blood pressure," Erwin thought as he put his hand on his head. "Gonna have a heart attack at 36."

**Notes for the Chapter:**

> I guess I'm sorta lost on where to go with this now. It was never meant to be more than a one shot... I'll try to wrap it up in the next few chapters or so.


	5. Chapter 5

The sun was rising on the horizon. Erwin sat on the rocks, rubbing lotion on his skin. The salt was harsh on a daily basis. Petra had given him this lotion with a pitying look. 

It smelled like flowers. Erwin grimaced. It was so Petra to have flowery scented everything. 

Eren was late. He sighed and kicked at the water. It was chilly, making Erwin wish he'd worn his wetsuit. It was much too cold to swim without it. 

A hand reached up and grabbed his ankle out of nowhere. A brown ponytail and human glasses popped out of the water. A...female mermaid? 

Eren came out of the water shortly after, a sheepish grin on his face. 

"Sorry...but this is Professor Hanji."

The woman grabbed both of Erwin's hands and began talking excitedly. 

"So, you're the one our little Eren has imprinted on, eh? Like he said, I'm Hanji Zoe."

His professionalism kicked in over his shock. "Hello. Erwin Smith, resident oncologist down at St. Maria Hospital. Pleased to meet you, Professor Hanji."

They began talking about past human and mermaid relationships. The professor knew very little about how the recorded relationships had ended, but she did know of a way to tattoo humans that had been imprinted on by mermaids. 

She pulled him down and whispered something harshly in his ear. Eren strained to hear but she was speaking too softly. Erwin's eyes widened in shock. She released him and spoke again at a louder volume. 

"We can do the ritual in 3 months if you want to. Either one. So you have time to decide," she said.

After she left, Eren and Erwin laid together head to head on the shore, fingers intwined. Erwin stroked the webs in between the boy's fingers and along his wrist. 

The tattoos still pulsed with his heartbeat. Eren rested his head on Erwin's shoulder, seawater seeping into the man's shirt. 

"What are we going to do?" He whispered. 

Erwin just shook his head. His mind was racing. 

Hanji's words echoed. "I found an old ritual in our archives. I'm not sure if it's possible, but it claims to turn imprinted humans into mermaids during the waning moon of the winter solstice. It's very unlikely that it'll actually work. Keep that in mind if that's what you want to do."

Eren stared at him with concern etched on his face. 

"Erwin?"

He shook his head to clear the professor's words. 

"Sorry. I'm just thinking," he said as he ran his fingers down the boy's face. The tattoos swirled under his soft touch. Eren's eyes were bright and watery with worry. 

"It'll be okay," he promised, pressing a kiss to the brown haired boy's salty forehead. 

They laid that way until cars started pulling up in the lot. Eren slid back into the water. Erwin pulled him forward into a soft kiss. Eren tasted of salt and Erwin of coffee and mint. 

Kids screamed in the background, jumping in the freezing water with excited yips. Erwin released the mermaid. Eren sighed wistfully before sinking back into the ocean. 

He didn't want to always have their visits cut short like this by people. If only...


	6. Chapter 6

Eren dove back down in the water. He hid behind a coral formation just at the surface and watched Erwin walk away. 

He swung his hips too much. Probably an old injury that affected his walk. But he did have a nice ass, Eren thought. 

He wasn't being careful. A net came down over his head before he could react. 

A loud laugh echoed out. It sounded like a horse's neigh. 

"Marco! We caught it!" He shouted, tugging at the net. Eren snarled in the net, curling his hands around the thin nylon netting. 

As the dark haired boy, assumedly Marco, and the horse boy pulled Eren out of cove, he had a sinking feeling that he wouldn't be coming back. 

 

Erwin went straight from the beach to Levi's house. Levi was what one could call a best friend, at least as much as the short and grumpy could be. 

The blonde man knocked on the door. It opened to reveal a stern faced man. 

"Erwin. Come in. Take off your shoes."

He did as instructed and followed Levi into the living room. They sat down on the couch. They visited and caught up the news of work and a lack of either of their love lives. 

People assumed they were gay in high school since they had no interest in dating. 

Levi was a chiropractor now. He was grumpy and angrily dispositioned, so he could only work with easy tempered clients who knew he didn't mean badly with his gruff comments. 

As Erwin was leaving, a couple was walking down the street, excitedly chattering. 

"I can't believe it Jean! After all out searching, we finally caught one!" One of them was saying. Erwin was unlocking when one of them bumped into him. 

"Excuse me," he said distractedly, too caught up in what his boyfriend was saying. 

Erwin sat in his car for a few minutes, a horrible feeling washing over him. But Eren wouldn't be in the cove, not in full daylight. He would have to wait till morning. 

 

When morning finally came, Erwin couldn't get to the cove fast enough. It was empty. Erwin collapsed on the sand, huffing. 

He heard a small splash and whipped his head up. Hanji leaned against a rock, glasses askew. 

"Erwin. Glad I caught you. Where's Eren?"

Erwin shook his head in confusion. "I don't know. I just got here. He's usually waiting by now."

She narrowed her eyes. "He didn't come home last night. I thought you may know where he is."

"He dove down when I left. I assumed he would've gone home."

"He always comes to me after your visits. I've been researching into the ritual. Apparently it's hit or miss. Either you get accepted as one of us and get the tattoos, or the ritual kills you. I think he saw that journal and freaked."

Erwin shook his head. "He doesn't spook that easily, I wouldn't think. But what do you think happened? Where could he be?"

"That's why I wanted to talk to you. I have a horrible feeling that he was captured. He's not the type of boy to not come home if he's upset."

Someone pulled into the parking lot. She hissed, baring sharp teeth. 

"Shit. I gotta go. Keep an eye out for him, Erwin." And she dove down. 

 

When Erwin was driving home, he got stuck in traffic around the main square. There were people gathered around something glowing blue. It reflected on the skyscrapers. 

The cars weren't moving so he parked. Might as well see what all the fuss is about. He pushed through the murmuring people till he got to the edge. 

He was shoved forward and fell over over stanchion rope. It had dropped down from people shoving against it. 

He pushed himself up on his elbows and looked up into a giant tank. It was a giant fishtank. His eyes widened as he looked up. His eyes met with familiar blue ones. Eren's. Eren. Both of their mouths dropped open. 

No. 

Oh god. No. Eren.


	7. Chapter 7

Eren pressed his hands to the glass. He had bits of netting caught around his fins and limbs. His eyes were filled with panic and his mouth open in a soundless scream. 

Erwin reached and and pressed one of his hands against Eren's. The mermaid shoved himself back and swam towards Erwin, slamming himself against the glass. He did it again and again. 

"Eren! Stop it! QUIT IT EREN!" He yelled, getting up on his knees, nose pressed against the glass. 

A loud voice boomed over the square. 

"Attention attention! Welcome, everyone, to the one and only exhibit of a real life mermaid! Welcome...to FISHTANKS AND TAILFINS! AN EXHIBIT SHOWING A MERMAID CAUGHT RIGHT HERE AT SHIGANSHINA BEACH!"

Eren swam in circles, trying to cover his ears. The vibrations must have been hurting him. 

The mic buzzed, letting out a high pitched squeal. Eren screeched, a warbled and high wail. Everyone in the square had to cover their ears. 

The man who had the mic dropped it, making it squeal again when it hit the floor. 

Erwin stormed up to the stage and grabbed the man by the collar and lifted him up. 

"Who the FUCK do you think you are?"

He spluttered, "What?!"

Erwin pointed at the tank. "Release him. Now."

The man sneered. "He's gonna make me so much money. Now get off me," he growled as he shoved himself away from the angry blonde. 

"Now. Right then. Let's get this show on the road," he said as he picked up the mic. "Go enjoy. It's just a fish."

"I'll be your announcer for today's show. My name is Jean Kirstein and I'll be conducting this show with my partner, marine biologist Marco Bott! And here he will be now, going into the tank to tame our mermaid."

A spotlight swept up to a dark haired man in a wetsuit balanced on the edge of the tank. 

"He'll be calming down the fish boy after our mic incident and performing a taming dance."

The man diving in as Erwin watched him horror. Eren moved in, moving faster than anyone expected. 

"Eren! No!"

But the mermaid had his teeth at Marco's right eye and his claws digging into his right arm. Eren bit into his eye, ripping out part of his cheek. His nails dug in deeper to the flailing man's arm. Blood was making the water hard to see through. 

Jean screamed and ran to the tank, pounding against the glass and screaming for Eren to stop. 

Erwin snapped out of his daze and ran up the ladder. He discarded his shirt and dived in the tank. Marco wasn't moving when he got to him. 

He felt a tearing on his left arm and kicked out. His leg connected with a solid scaly tail. Eren let go, realizing it wasn't another performer. 

Eren twined his tail around Erwin and pulled him forward into a kiss. Erwin gasped against the shaking mermaid. He was out of air. 

Eren took Erwin's face in his hands and blew oxygen into his mouth, like he did at the cove so many weeks ago. 

But the water was getting redder and Erwin's vision was getting blurrier. Oxygen wouldn't help with blood loss. Eren panicked, his tattoos swirling faster and faster. 

He dragged Erwin up to the surface and began yelling. 

"Get a healer! Someone! Help!"

The crowd stared at the mermaid, all wide eyed and in shock. The announcer, Jean, was sobbing against the tank. 

"Please, help him!" Eren cried out. Someone rushed forward out of the crowd and started pulling Erwin out of the tank. People sprang into motion, trying to help the bleeding man. 

Eren threw his arms over the top of the glass and watched in horror as an ambulance was called. They took away the dead man, Marco, and the love of Eren's life. He caused this. 

He began to sob. The water was pink. This was all his fault. 

A man stepped up to the tank. A short man with an angry face. 

He climbed up the ladder and yanked Eren's head up. "Oi, brat. How long can you live out of water?"


	8. Chapter 8

Erwin woke to a sharp pain in his right shoulder and a feeling of...loss? He sat up quickly and gasped out, "Eren!"

Levi stirred from a corner chair. "Calm down. Your fishy boy is back home," he said as he got up and pushed Erwin back down. 

"Wait, what?"

Levi sighed in exasperation. "Blah blah, I put the dirty thing in the back of my pickup and now everything I own smells like dead fish and seaweed. You're welcome."

Erwin laughed at his abruptness. "Thanks, Rivaille."

 

Erwin was released from the hospital a week later with one less arm than he entered with. The doctors had to amputate it due to irreparable nerve damage. He had about half of his upper arm still. 

The marine biologist Marco Bott reportedly died of unknown causes and the mermaid boy dismissed as a simple circus trick. Jean Kirstein was tried at court for the murder of his partner and husband but was not proven guilty. He disappeared shortly post trial after giving the rest of his life savings to the Bott family. 

Erwin Smith, the man who supposedly dived in the tank after Marco, quit his job after being released from the hospital. 

His best friend Levi Ackerman released a statement saying, "it's none of the media's god damn business what he did. Don't bother me again," when asked. 

But he was often at the edge of a cove in the early morning, drinking his coffee with his feet in the water. 

 

The mermaids have a new lore of human turned into a mermaid through a mermaids sacrifice of their tail. After historian Hanji went missing, it was never confirmed. 

Eren left his family and tribe for an unknown mermaid missing an arm shortly after being returned to the sea by a short black haired human. He took Hanji's research on humans with him. 

Hanji, on the other hand, with her new legs and a grumpy human boyfriend, was ecstatic to have an entire new species to study. She went into sociology to study the behavior of humans, much to Levi's dismay. 

Erwin and Eren, well, they got their happy ever after. 

The end.

**Notes for the Chapter:**

> And there we have it. The end. Thank you for reading. Please leave me a kudos if you enjoyed and a comment if you love making me happy.

**Author's Note:**

> Um, so yeah. First story on AO3 is eruren. I love this pairing. Besides, it's only going to be like, a 5 year age difference in this fic, so it's not as weird. 19 year old Eren and 24 year old Erwin.  
> Thanks for reading,  
> Idk if I'm going to post any other chapter,  
> The Social Experiment


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